1. Field of the Invention
Embodiments of the present invention relate to a pixel and an organic light emitting display using the same, and more particularly, to a pixel capable of displaying an image with uniform brightness and an organic light emitting display using the same.
2. Description of the Related Art
Recently, various flat panel displays (FPD) capable of reducing weight and volume that are disadvantages of cathode ray tubes (CRT) have been developed. The FPDs include liquid crystal displays (LCD), field emission displays (FED), plasma display panels (PDP), and organic light emitting displays.
Among the FPDs, the organic light emitting displays display images using organic light emitting diodes (OLED) that generate light by re-combination of electrons and holes. The organic light emitting display has high response speed and is driven with low power consumption.
The organic light emitting display includes a plurality of pixels arranged at intersections of a plurality of data lines, scan lines, and power supply lines in a matrix. Each of the pixels commonly includes an organic light emitting diode (OLED) and a driving transistor for controlling the amount of current that flows to the OLED. The pixels generate light components with predetermined brightness components while supplying currents from the driving transistors to the OLEDs to correspond to data signals.
However, in a conventional pixel, when a white gray scale is displayed after realizing a black gray scale as illustrated in FIG. 1, light with lower brightness than desired brightness is generated in a period of about two frames. In this case, an image with desired brightness is not displayed by the pixels to correspond to gray scales so that uniformity in brightness deteriorates and that picture quality of a moving picture deteriorates.
As a result of experiment, deterioration of the response characteristic of the organic light emitting display is caused by the characteristic of the driving transistors included in the pixels. That is, the threshold voltages of the driving transistors are shifted to correspond to voltages applied to the driving transistors in a previous frame period. Due to the shifted threshold voltages, light components with desired brightness components are not generated in a current frame.